DESC: Koss, a leading manufacturer of high-fidelity stereophones, is pleased to introduce the CS100 stereo headset with electret, noise cancellation microphone for hands-free communication from your personal computer. It is ideal for telephony, voice-activated and voice recognition software and computer games with sound cards with built-in bias supply. But it can also be used with an external power source if sound card does not have a built-in bias supply. CS100's Clear Voice Technology noise cancellation microphone delivers clear communication in noisy environments. Other features include dynamic element for extended frequency response, foam ear cushions for open, hear-through sound, adjustable headband for best fit and straight, single entry cord.